This multi-center study is to determine for adult patients who have growth hormone deficiency if daily somatropin treatment for 2 years will improve bone tissue in the spine compared to daily treatment with placebo; if daily somatropin treatment for 2 years will improve bone tissue in the hip and show evidence of beneficial bone effects found in blood samples; if daily somatropin treatment for 6 months will show changes in your feelings of well-being; information on somotropin side effects.